Data grid offer ease of accessibility to data by exposing a simple data structure—a cache—in which objects can be stored. In a distributed mode where caches cluster together, a large memory heap can be exposed. This is more powerful than simple replication in that it distributes a fixed number of replicas of each entry—providing resilience to server failure—as well as scalability since the work done to store each entry is fixed in relation to cluster size.
Because the data structure is shared, each cache node needs to be synchronized with other cache nodes. Prior solutions involve locking up the system (e.g. preventing any changes) while data is being synchronized.